1. Field
The invention is in the field of microscope systems for observing the movement of small particles.
2. State of the Art
Microscopes are well known and in wide use for viewing small particles. If the particles are rapidly moving, however, it becomes very difficult, and in most instances impossible, to study or photograph the particles. This is particularly true if it is desired to size and determine velocities of particles emanating from the nozzles of spraying devices, such as spray cans.
In designing spray cans and in developing products to be dispensed by spray cans, it is desirable to know the sizes of particles being dispensed and their velocity. This information is useful to determine whether the material is being dispensed in a manner suitable for the particular product concerned, whether the sprayed material reaches its intended target, and how much of the material is dispensed in particle sizes small enough to become suspended in the air and inhaled.
A system has been developed recently which utilizes a television camera and a laser to observe particles in aerosol sprays for obtaining the desired information. The laser produces a series of short, high energy pulses, which travel through an image plane to the television camera. The laser acts as a strobe to stop the action of the particles as they move, and produces a free running series of pulses. However, many of the pictures produced by the television camera are useless. This is because a light source such as a laser produces a large amount of electromagnetic energy which is radiated along with the light from the light source. This electromagnetic radiation effects the electronics in the television camera so as to destroy a portion of the picture when the pulse occurs. Also, each time a light pulse occurs a new picture is taken so that many pictures produced by the camera are half one picture and half another. Distortion of the particles in the pictures is often great, resulting in poor particle resolution. Moreover, the system is useful only for sizing the particles. No system has been available for measuring the velocities of the particles.